where is basilosaurid whales nasal opening where is basilosaurid whales nasal opening

In Georgiacetus, the only limb element known is the pelvis, and it appears to not have been connected to the vertebral column, suggesting that these limbs could not support the animal's weight. The new find of aquatic behaviors in raoellids suggests that these animals used the water as a refuge against danger. In most mammals, its walls are made of a bone called the ectotympanic, as is the case in artiodactyls and cetaceans. These embryos are not drawn to scale. is started on 4L4 \mathrm{~L}4L oxygen by nasal cannula and an IV of D5W at 15mL/hr15 \mathrm{~mL} / \mathrm{hr}15mL/hr. The skeletons of Ambulocetus (top) and Pakicetus (bottom), J.G.M. 482. common ancestor with. List five independent nursing interventions that may help relieve B.T. Bajpai S, Thewissen JGM. Strauss, Bob. Whether the hind limbs were functional is unclear; well-formed joints and evidence of muscle attachments on the bones suggest that they may have been functional, but they also may have been completely atrophied. Just like Pakicetus, ambulocetids had osteosclerotic limb bones (Madar 1998). 2002;22:40522. reptile-like creatures B.T. Adam Li / NOAA/NMFS/SWFSC. They were probably the first fully aquatic cetaceans. Counter current heat exchange evidence is also found for the tongue and the testes of dolphins. What is one way Scientists know that Maiacetus lived in the ocean? Strauss, Bob. Google Scholar. Provided by the Springer Nature SharedIt content-sharing initiative. Open Access This article is distributed under the terms of the Creative Commons Attribution 2.0 International License (https://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In general, the diameter of these tubes, the semicircular canals, scales with body size (Spoor and Thewissen 2008), but the canals are extremely reduced in modern cetaceans. This form of locomotion is anguilliform, or eel-like; in the case of Basilosaurus, this movement would have been up-down, rather than side to side as in eels and other anguilliform fishes. Fossils of ambulocetids can be classified in three genera, and remains of these have been found in Northern Pakistan and northwestern India. Studies the geographic distribution of different species. The postcranial skeleton of remingtonocetids (Bajpai and Thewissen 2000) shows that these whales had short legs but a very long powerful tail. Conclusive paleontological evidence shows the way in which the nasal openings were moved in the course of phylogeny (see Kellogg 1928; Slijper 1962; Gaskin 1976; Oelschlager 1978, 1987, 1990; Moore 1981). "10 Facts About Basilosaurus." 1994, 2001b; Fig. Reproductive biology and phylogeny of Cetacea. structures that have different mature forms in different organisms but develop from the same embryonic material, A structure that is present in an organism but no longer serves its original purpose, the study of the formation, early growth, and development of different organisms, provides evidence about the history of lfe on Earth, also shows the adaption of animals over time, the study of the earth's physical and cultural features, David N. Shier, Jackie L. Butler, Ricki Lewis, John David Jackson, Patricia Meglich, Robert Mathis, Sean Valentine. This explains the unusual length and flexibility of Basilosaurus' front flippers, which retained their rudimentary elbows. Whales, Dolphins, Porpoise. Basilosaurus drazindai and Basiloterus hussaini, new Archaeoceti (Mammalia, Cetacea) from the middle Eocene Drazinda Formation, with a revised interpretation of ages of whale-bearing strata in the Khirthar Group of the Sulaiman Range, Punjab (Pakistan). Just like raoellids and all cetaceans, pakicetids have an involucrum, the thickened inner lip on the tympanic bone (Fig. Basilosaurid forelimbs have broad and fan-shaped scapulae attached to a humerus, radius, and ulna which are flattened into a plane to which the elbow joint was restricted, effectively making pronation and supination impossible. A rete mirabile (Latin for wonderful net; plural retia mirabilia) is a complex of arteries and veins lying very close to each other, found in some vertebrates. 2006;103:84148. In all mammals, this bone, the astragalus or talus (Fig. Protocetids are known from low latitudes of Asia, Africa, Europe, and North America, and it is likely that they had a worldwide distribution in the middle Eocene between 49 and 40 million years ago (Gingerich et al. Three species of Basilosaurus are known, and specimens have been discovered in fossil sites in the southeastern United States (Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, and Tennessee), England, Egypt, Jordan, and Pakistan, indicating that Basilosaurus inhabited the Northern Atlantic Ocean, Tethys Sea, and the Paratethys Sea (the precursor to the Mediterranean Sea). Such a locality is called a bone bed, and it is not possible to determine which skull went with which other bones. In: Prothero DR, Foss SE, editors. Peters, S.E., Antar, M.S.M., Zalmout, I.S., and Gingerich, P.D. (2021, February 16). In pakicetids, the eyes faced upward, whereas in Ambulocetus, they face toward the sides, although they are still located high on the skull (Nummela et al. Basilosauridae is a paraphyletic family of extinct cetaceans that lived during the late middle to the early late Eocene, known from all continents. What would be considered the strongest evidence that two species are related to one another? Basilosaurids occurred worldwide during most of their history, and important fossils have been recovered in Egypt and the southern United States. The changing cetacean body plan during the first ten million years of cetacean evolution. We thank the Geological Survey of Pakistan for collaborating in collecting and studying Pakistani fossils and for logistic support, and Dr. S. Taseer Hussain for his leadership of the Howard University-Geological Survey of Pakistan project. It may seem odd that a 47-million-year-old artiodactyl that looks like a tiny deer is aquatic, but this behavior is reminiscent of one species of modern artiodactyl. We thank Ajay Thakore and the Gujarat Mining Development Corporation for assistance with fieldwork in Gujarat, and Mr. Bhatti of Bhuj for help with logistics. His current research is on trait-based community dynamics in vertebrates, Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. Basilosaurus was an unfamiliar, long snake like animal. Write each sum in sigma notation. A new middle Eocene protocetid whale (Mammalia: Cetacea: Archaeoceti) and associated biota from Georgia. We also thank the Department of Wildlife, North Slope Borough, and the Barrow Arctic Science Consortium for logistic support and assistance in the acquisition of specimens. At the same time, a long rost rum with narrow jaws develops. Whales originated from aquatic artiodactyls in the Eocene epoch of India. Based on the difference in time between the perception of a sound wave in each ear, Basilosaurus could likely determine the direction of origin of incoming sound. As cetaceans became more aquatic, the nasal bones retracted and the nasal opening migrated to the top of the skull and became the blowhole (modified from Thewissen and Bajpai 2001b). 1st ed. The study of differences and similarities between living things. 18). coat of fur ____________ ______________Both have? These are clear signs of their mammalian heritage. Once cetacean hindlimbs were no longer needed, it could have taken millions of years before they were lost entirely, with a protracted period of highly reduced hindlimbs. The time of origin of whales and the role of behavioral changes in the terrestrialaquatic transition. Many features that are common in land mammals have changed in the evolutionary process that led to cetaceans. Sound waves passed into the fat pad through the thin bone of the lower jaw and then continued to the middle and inner ear. Modified from Spoor et al. Dolphins, pilot whales and sperm whales use echolocation clicks to hunt and subdue their prey. In spite of our advances in understanding of the pattern of cetacean origins, it remains unclear which process caused this pattern: Why did cetaceans enter the oceans? The first embryo is 6mm, the last one 17.5mm in length. VIDEO ANSWER:Hello. Thewissen JGM, Nummela S. Sensory evolution in aquatic tetrapods: toward and integrative approach. The African mouse deer (Hyemoschus aquaticus) lives on the forest floor of central Africa, feeding mostly on fruits and flowers. 2001b). Manage cookies/Do not sell my data we use in the preference centre. Rivers may have brought sediment into this bay, and the water may not have been transparent. The emergence of whales: evolutionary patterns in the origin of Cetacea. Modular evolution of the Cetacean vertebral column. New York: Plenum; 1998. p. 23567. The tympanic bulla, a bone which forms the floor of the middle ear cavity, was less connected to the rest of the skull as compared to more primitive whales. In other regards, these three groups are dissimilar. The largest basilosaurids may have been as long as 25 metres (82 feet). For many of these, no complete skeletons are known, but it appears clear that protocetids were a diverse family, with great variety in such features as snout length and ear morphology. 1998; Clementz et al. _______________________________ Where is the nasal opening in Get 5 free video unlocks on our app with code GOMOBILE, _______________________________ Where is the nasal opening in Nature. For instance, they all have streamlined bodies, short limbs, and fin-shaped hands and feet. CAS 2001b; Buchholtz 1998). The oldest representatives of the Remingtonocetidae are found at the same fossil localities as Ambulocetus, but the greatest diversity of remingtonocetids is known from younger rocks, between 48 and 41 million years ago in India and Pakistan (Gingerich et al. 2004;34:1222. Locomotor abilities in water may also differ between protocetids. Bones shown here are derived from several individuals and were found scrambled with many other bones near the border area between Pakistan and India by geologist A. Ranga Rao ( J.G.M. The emergence of whales, evolutionary patterns in the origin of Cetacea. Just like Indohyus, limb bones of pakicetids are osteosclerotic (Madar 2007), also suggestive of aquatic habitat, an interpretation consistent with stable isotope evidence (Roe et al. [7] Some genera tend to show signs of convergent evolution with mosasaurs by having long serpentine body shape, which suggests that this body plan seems to have been rather successful. Anatmia - latin kifejezsek (alapszvetek), John David Jackson, Patricia Meglich, Robert Mathis, Sean Valentine, BIO 101 - How Populations Evolve, Part 2 (2), Plant Biology Exam 2- Evidence for Evolution. Curiously, the ribs of Basilosaurus are very dense and thickened, which is a specialization that probably allowed it to achieve slight negative buoyancy. Structural adaptations of early archaeocete long bones. These are two species of extinct basilosaurid whales! Nature. While we believe that there are some benefits to this view, we lean against it. . It was not until 2001 that skeletons of these whales were discovered (Thewissen et al. A remarkable video of this behavior is posted on www.youtube.com and is called Eagle versus Water Chevrotain (chevrotain is the French name for African mouse deer). The skeleton of Ambulocetus suggests that it swam by moving the hind limb and tail in dorsal and ventral undulations. Nature. Form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve, form of natural selection by which the center of the curve remains in its current position; occurs when individuals near the center of a distribution curve have higher fitness than individuals at either end, form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle, the arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores. Clementz MT, Goswami A, Gingerich PD, Koch PL. Proc Natl Acad Sci USA. 20). Let us know if you have suggestions to improve this article (requires login). [3] While they were unable to support body weight on land, they might have assisted as claspers during copulation. Archaeocete whales have been found from early to middle Eocene (52-42 Ma) deposits in Africa and North America but are best known from Pakistan and India. Thewissen JGM, Bajpai S. Dental morphology of the Remingtonocetidae (Cetacea, Mammalia). Pakicetus Edward Babinski has some good pages. 2007). B.T., a 222222-year-old man who lives in a small mountain town in Colorado, is highly allergic to dust and pollen. With the origin of protocetids, cetaceans spread across the globe. On the other hand, whereas the main propulsive organ of cetaceans and sirenians is the tail, sea lions swim with their forelimbs, and seals with their hind limbs. The fact that the cetacean nose moved, in the course of evolution, from the tip of the rostrum up to the vertex of the head, is among the most perfect of adaptations to aquatic life. Proc US Natl Mus. Ambulocetus fossils have only been found in rocks that were formed in a shallow sea, possibly in a coastal swamp or forest. Developed by Carl Linnaeus who used Greek and Latin names. Most modern cetaceans have a relatively stiff neck, and it is likely that this reflex, if present at all, cannot stabilize the head because the neck is already relatively immobile. Sequence stratigraphic control on preservation of late Eocene whales and other vertebrates at Wadi Al-Hitan, Egypt. Figure2 shows four embryos arranged from young to old. Given its morphology, it appears that Indohyus is more aquatic than Hyemoschus and may have spent much of its life in water. Shifting continents 34 mya created large-scale changes in ocean currents and temperatures that coincided with this diversification. (2002). We will discuss these following the order of the cladogram. This happened in 2007, when skeletons for raoellids were found in the Himalayas that were shown to be the closest relatives to whales (Thewissen et al. Cranial anatomy of Pakicetidae (Cetacea, Mammalia). In: Mazin J-M, Buffrnil VD, editors. In modern bowhead whales (pictured here is the pelvis of an adult male, B. mysticetus, 98B5), the acetabulum and obturator foramen are lost and the ilium is reduced. J Vert Pal. 1997;23:48290. In: Thewissen JGM, editor. 2005). amphibian-like creatures f fish share a Remingtonocetids and all cetaceans higher on the cladogram have small canals, but pakicetids have large canals. 2006). As such, it may give cetaceans the opportunity to be acrobatic. Reducing the size of the canals would reduce the chances of overstimulation and also limit the sensitivity of the canals. Cetaceans probably followed the gray path on the left. Buono M, Fordyce R.E., Marx F.G., Fernndez M.S. Such a diagram is called a cladogram. 1998). Cetacean fossils have been recorded from middle and late Eocene deposits on Seymour Island since the beginning of the twentieth century and include fully aquatic Basilosauridae and stem Neoceti. The transition from raoellid to pakicetid and thus from artiodactyl to cetacean was a remarkable event that included the wholesale rebuilding of the skull and its food-processing equipment. The former species were larger and had larger eyes (Fig. This is consistent with the environmental evidence from the rocks that the fossils are found in. The foramen is enormous, covering nearly the entire depth of the jaw in modern cetaceans and remingtonocetids, unlike pakicetids, where it is smaller (Fig. Baltimore: Johns Hopkins Univ Pr; 2007. p. 1931. Google Scholar. Skulls and skeletons are known for a single raoellid: Indohyus (Thewissen et al. Porpoises belong to the modern family Phocoenidae, and are one of the less diverse 'families' of modern echolocating whales (Odontoceti), with six species in three genera. There are approximately seven genera of basilosaurid cetaceans, but basically they can be divided into two body types. Fish FE. Notice the similarities between hippos and whales. 2007;290:71633. Diagram showing the relationships among cetaceans and their land relatives. (C) The pelvis is attached to the femur with a synovial joint, and a small cartilaginous tibia is also present (B. mysticetus, 06B4; Lucas 1900; Struthers 1893). Eg: when we looking at the whales's anatomy, we can see that they evolved from an ancien 4 legged land mammal. Skeletal evidence indicates that Basilosaurus could perceive the direction of origin for underwater sounds. 2002;417:1636. Basal fully aquatic whales, the basilosaurids are worldwide known from BartonianPriabonian localities, indicating that this group was widely distributed during the late middle Eocene. 1st ed. Comparing things that are similar and different. Llanocetus denticrenatus was discovered in the latest Eocene sediments of Seymour Island, Antarctica and current research puts it as the earliest known Mysticeti or baleen whale. Sirenians are most closely related to elephants, and pinnipeds are related to land carnivores (e.g., dogs and bears). Retrieved from https://www.thoughtco.com/facts-about-basilosaurus-king-lizard-whale-1093325. As huge as Basilosaurus was, it still occupied a fairly low branch on the whale evolutionary tree, plying the oceans only 10 million years or so after its earliest ancestors (such as Pakicetus) were still walking on land. 1990. Nature. Univ Michigan Pap Pal. Modern whales emerge Mysticetes and Odontocetes (33-28 mya) The ancestors of toothed and baleen whales diverged as the world's climate rapidly cooled and opened up new opportunities for basilosaurid diets. Evolutionary history of cetaceans: a review. In modern dolphins, on the other hand, it is located on the top of the head, above the eyes. This locality is a bone bed, scattered with fossils from many different animals (Fig. Synopsis of the earliest cetaceans: Pakicetidae, Ambulocetidae, Remingtonocetidae, and Protocetidae. ThoughtCo, Feb. 16, 2021, thoughtco.com/facts-about-basilosaurus-king-lizard-whale-1093325. You can find out more about our use, change your default settings, and withdraw your consent at any time with effect for the future by visiting Cookies Settings, which can also be found in the footer of the site. The first embryo shows forelimbs but not hind limbs (in most mammals forelimbs develop before hind limbs). The second body type among basilosaurids is shorter, as short as 4m. These basilosaurids, called dorudontines (Uhen 1998), had dolphin-shaped bodies and swam by up-and-down motions of their tail fluke. Let's hear questions in a question they were asking that so that's a shark, whales and dolphins. The sediments at Locality 62 can inform us about the environment in which pakicetid whales lived (Aslan and Thewissen 1997) and in which more than 60% of the fossils are pakicetids (Thewissen et al. Given the large size of Basilosaurus and the thickness of the crowns and roots of the teeth near the tip of the snout, it may have preyed on other marine mammals, as does the modern killer whale. 2007) that they are related to cetaceans is insufficient reason to change that. By reading a z leveled books best pizza sauce at whole foods reading a z leveled books best pizza sauce at whole foods another animal is to ? The great length of the vertebral column of basilosaurids can be attributed to the increase in the number of lumbar vertebrae in the taxon but also by the increase in length of each individual vertebra. While Indian localities suggestive of a muddy lagoon with abundant plant growth (Bajpai et al. 1997;25:26177. Copyright The Pandas Thumb and original authors Content provided under Creative Commons BY-NC-ND License 4.0. River otters swim with their hind limbs and tail, and it is likely that Ambulocetus did the same. Bringing Georgia's Natural History to Georgians, GA Paleo Research by Paul F. Huddlestun PhD, Late Eocene & Older Coastal Plain Stratigraphy, Washington County Core Logs By Paul Huddlestun, Coastal Plain Core Logs by Paul F. 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All of the basilosaurids share some common features despite significant variations in size. A new protocetid whale (Cetacea, Archaeoceti) from the late middle Eocene of South Carolina. Madar SI, Thewissen JGM, Hussain ST. Additional holotype remains of Ambulocetus natans (Cetacea, Ambulocetidae), and their implications for locomotion in early whales. Bajpai SB, Thewissen JGM. 2007). Humans and chimpanzees share a recent common ancestor. The branching of the cetacean groups on this cladogram is consistent with most recent work (Thewissen et al. 1995b;29:291330. O'Leary MA, Uhen MD. Notice the similarities between hippos and whales. Geisler JH, Uhen MD. In this and many other special adaptations of their morphology and physiology, cetaceans surpass most primarily aquatic animals even though they themselves have developed from land mammals that breathe with lungs, and have only secondarily conquered the aquatic environment. Ancestral whales also have their nose opening near the tip of the snout, and the shift to the forehead is documented evolutionarily by fossils. police officer relieved of duty. Thewissen JGM, Cohn MJ, Stevens LS, Bajpai S, Heyning J, Horton WE Jr. Developmental basis for hind limb loss in dolphins and the origin of the cetacean body plan. 24). Scientists are still trying to understand what exactly these differences mean, but they must have affected function of the animals in a major way. Science. It contains a small group of species, most of which are only known from teeth and jaws (Thewissen et al. 27). There are several recent reviews of the evolution of odontocetes and mysticetes (Fordyce and Muizon 2001; Bianucci and Landini 2007). This bone surrounds the middle ear cavity like a bowl. In spite of this record, there is room for much more research. It is like a recipe to show who is related to who. 1998; Clementz et al. Basilosaurus (a.k.a. This feature makes the bones heavy, and heavy bones make running on land more difficult. Its overall body shape is so unlike those of other whales that it was initially thought to be a marine reptile; hence the name Basilosaurus, which means king lizard. The teeth towards the back of the mouth have multiple large serration-like cusps. Therefore, externally, remingtonocetids may have resembled enormous otters with long snouts (www.neoucom.edu/DEPTS/ANAT/Thewissen/whale_origins/whales/Remi.html). However, the rest of Basilosaurus hearing adaptations indicate it was fully marine, and thus any retention of adaptations for hearing airborne sound was probably vestigial. This affects the attachment of the masticatory muscles but also the path of the nerves going to eyes and nose. One hearing-related feature is the size of the mandibular foramen, a perforation of the lower jaw behind the teeth. What is one way Scientists know that Maiacetus lived in the ocean? Cour Forsch Inst Senckenberg. Sharks, whales, and dolphins share similar features such as body shape and the position of fins. Accept Cookies, Osteopathic Manipulative Medicine Research. another animal is to ? Basilosaurids are usually referred to as archaeocetes, the ancient whales, but in modern classifications they are members of the Pelagiceti, the fully aquatic whales. The emergence of whales: evolutionary patterns in the origin of Cetacea. The rocks in which these fossils are preserved indicate that the bones were buried in a freshwater stream. Nasal Drift in Early Whales Whales breathed with more ease when they no longer had to lift a snout above water. First described in 1834, it was the first archaeocete and prehistoric whale known to science. New whale from the Eocene of Pakistan and the origin of cetacean swimming. In addition, the hind limbs may have been used as claspers to help guide the long bodies of the males and females into position for mating. Astragali (bone of the ankle) of the raoellid Indohyus (RR 224), the pakicetid Pakicetus (H-GSP 98148), a modern pig (3/84), and a modern deer (2/93). Fetus of the pantropical dolphin (LACM 94389, Stenella attenuata) with whiskers along the rostrum. Cookies collect information about your preferences and your devices and are used to make the site work as you expect it to, to understand how you interact with the site, and to show advertisements that are targeted to your interests. They appear to have lived side by side roughly 34 to 40 million years ago. Raoellid teeth are very different from those of early cetaceans, suggesting that a dietary shift took place after the habitat change and may have been critical in the early diversification of cetaceans but not in their entry into the water. Both raoellids and pakicetids had aquatic adaptations, wading and walking in freshwater streams. Geisler JH, Saunders AE, Luo Z-X. 1st ed. Gingerich PD, Raza SM, Arif M, Anwar M, Zhou X. Roe LJ, Thewissen JGM, Quade J, O'Neil JR, Bajpai S, Sahni A, et al. Notice the similarities between hippos and whales. In Eocene Basilosaurus-bearing fossil sites in Egypt, many fossils of the smaller basilosaurid Dorudon bear large puncture marks, which are potentially caused by the teeth of Basilosaurus. common ancestor with, ANSWER 1. 2007). That this evolutionary process is repeated in a way during ontogeny became obvious through external observations on embryos and fetuses (Kukenthal 1893). Stable isotope data indicate that Ambulocetus lived in environments that were partly freshwater, possibly implying that they were near a river mouth (Roe et al. 12). This early whale has short and powerful legs, with five fingers in the hand and four toes in the foot. 2006; Madar 2007; Fig. Munich: Verlag Friedrich Pfeil; 2001. p. 169233. As such, these teeth are not suitable for crushing food. Although not positioned at the tip of the snout like more primitive whales (e.g. 23) with large teeth, suggestive of a diet that includes hard elements (such as bones of large fish or other vertebrates). Form, function, and anatomy of Dorudon atrox (Mammalia, Cetacea): an archaeocete from the middle to late Eocene of Egypt. 2006). Pictured are five families of archaeocetes, the oldest being the pakicetids, while the youngest are the basilosaurids (modified from Thewissen et al. As archaeocetes, Basilosaurids lacked the telescoping skull of present whales. Form, function, and anatomy of Dorudon atrox (Mammalia, Cetacea) from the Middle to Late Eocene of Egypt. In this photo we are looking down at the top of a basilosaurid skull. It also exposes the inside of the middle ear, which is filled with sediment here. Preliminary evaluation of Kuldana paleosols and implications for interpreting vertebrate fossil assemblages, Kuldana Formation, Northern Pakistan. To see earlier posts, select the Archives at the top of this page. 1990. In the past, the presence of an ectotympanic with an involucrum was the main character supporting the inclusion of a species in Cetacea, and it is therefore sometimes advocated that Indohyus (or Raoellidae) be included in Cetacea. About 50 million years ago, during the evolution from (raoellid) artiodactyls to (pakicetid) cetaceans, a remarkable transformation took place. Cetaceans are unrelated to other marine mammals, the sirenians (manatees and dugongs) and the pinnipeds (seals, sea lions, walruses). The ectotympanic of artiodactyls roughly has the shape of half a walnut shell, enclosing the air-filled middle ear cavity. Basilosauridae is a family of extinct cetaceans. In all, there are four or five genera of remingtonocetids, characterized by a long snout, which makes up nearly two thirds of the length of the skull. The blowhole in modern cetaceans is located between the eyes on the forehead, an adaptation for breathing while remaining submerged.